9) Why does a teakettle make noise as the water approaches a boil? What determines the frequencies of sound?

Question

this has something to be with physics. the frequencies may seem to be higher as it approaches a boil.. i want to know what exactly happens in the kettle.

Answer 1

Mr. Wizard, I'm not, but I do know that the teakettle noise is steam bubbles collapsing back to liquid before escaping with a whistle. The higher pitch is due to the greater energy absorbed by the water and if it can't get higher, it gets LOUDER.
By the way, sound is at the very bottom of the electro-magnetic spectrum, which includes light, radio, etc.

Answer 2

its the steam that is blown into the hole and makes the kettle whistle when the water is boiled